Re: More info: 2.1.108 page cache performance on low memory

[Rik van Riel <H.H.vanRiel@phys.uu.nl>]

On 23 Jul 1998, Zlatko Calusic wrote:

> One wrong way of fixing it is to limit page cache size, IMNSHO.
> 
> I tried the other way, to age page cache harder, and it looks like it
> works very well. Patch is simple, so simple that I can't understand
> nobody suggested (something like) it yet.

These solutions are somewhat the same, but your one may take
a little less computational power and has a tradeoff in the
fact that it is very inflexible.

> --- filemap.c.virgin   Tue Jul 21 18:41:30 1998
> +++ filemap.c   Thu Jul 23 12:14:43 1998
> +                       age_page(page);
> +                       age_page(page);
>                         age_page(page);
> If I put only two age_page()s, there's still too much swapping for my
> taste.
> With three age_page()s, read performance is as expected, and still we
> manage memory more efficiently than without page aging.

This only proves that three age_page()s are a good number
for _your_ computer and your workload.

> Comments?

As Stephen put it so nicely when I (in a bad mood) proposed
another artificial limit:
" O no, another arbitrary limit in the kernel! "

And another one of Stephen's wisdoms (heavily paraphrased!):
" Good solutions are dynamic and/or self-tuning "
[Sorry Stephen, this was VERY heavily paraphrased :)]

Rik.
+-------------------------------------------------------------------+
| Linux memory management tour guide.        H.H.vanRiel@phys.uu.nl |
| Scouting Vries cubscout leader.      http://www.phys.uu.nl/~riel/ |
+-------------------------------------------------------------------+

--
This is a majordomo managed list.  To unsubscribe, send a message with
the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org